These slower speeds don't mean the winds circling the eye of the storm are slowing down.
The study in the journal Nature, finds a 10 percent slowdown in storm speed between 1949 and 2016.
The unusually slow-moving Hurricane Harvey was a recent example.
The Atlantic Basin remains inactive and the storm now has a zero threat to life or land.
"The slower the storm gets, the more rain an area will get", said Jim Kossin.
CDC report reveals more than 45,000 Americans took their own lives in 2016
That indicates a large portion weren't diagnosed, "which suggests to me that they're not getting the help they need", he said. California had an increase of 14.8 percent - the fifth-smallest, after Delaware, Maryland, Florida and North Carolina.
The study published in Nature this week by United States weather experts shows the problem weather systems are taking longer to travel across the planet. Adding last year's storms would have made the slowdown a bit more prominent, he said. "The storms will stay in your neighborhoods longer". The storms, in effect, are sticking around places for a longer period of time.
Kossin said the findings were of great importance to society.
Dr Christina Patricola, from the Climate and Ecosystems Sciences Division at University California, Davis, says the findings raise several questions, especially regarding "stalled" tropical cyclones. "Not quite like a cork in a stream, but similar", he said.
"These trends are nearly certainly increasing local rainfall totals and freshwater flooding", Kossin said, "which is associated with very high mortality risk".
Therefore, it would make sense that if the flow around the hurricanes and typhoons is moving slowly, the storms will also be moving slower, which Kossin believes is what he is observing in the data.
In a warming world where atmospheric circulations are expected to change, the atmospheric circulation that drives tropical cyclone movement is expected to weaken. "And, unfortunately, this signal would point to more freshwater flooding".